Effect of pectin and hemicellulose removal from hemp fibres on the mechanical properties of unidirectional hemp/epoxy composites

The objective of this study was to investigate the effect of pectin and hemicellulose removal from hemp fibres on the mechanical properties of hemp fibre/epoxy composites. Pectin removal by EDTA and endo-polygalacturonase (EPG) removed epidermal and parenchyma cells from hemp fibres and improved fibre separation. Hemicellulose removal by NaOH further improved fibre surface cleanliness. Removal of epidermal and parenchyma cells combined with improved fibre separation decreased composite porosity factor. As a result, pectin removal increased composite stiffness and ultimate tensile strength (UTS). Hemicellulose removal increased composite stiffness, but decreased composite UTS due to removal of xyloglucans. In comparison of all fibre treatments, composites with 0.5% EDTA + 0.2% EPG treated fibres had the highest tensile strength of 327 MPa at fibre volume content of 50%. Composites with 0.5% EDTA + 0.2% EPG → 10% NaOH treated fibres had the highest stiffness of 43 GPa and the lowest porosity factor of 0.04.     

Reactive extrusion: A useful process to manufacture structurally modified PLA/o-MMT composites

In the present work, poly(lactic acid) (PLA) sheets reinforced with organically modified montmorillonite (o-MMT) were manufactured through reactive extrusion-calendering using a masterbatch approach in a pilot plant. Reaction monitoring analysis suggests the occurrence of premature reactions between o-MMT and the reactive agent; lowering further structural changes in the polymeric matrix. While calendered sheets exhibited a homogenous and preferential distribution of clay particles in MD, the coexistence of mixed structures, involving tactoids of various sizes as well as intercalated clay layers was observed. However, a higher and finer dispersion of o-MMT particles was achieved through clay–polymer tethering via chain extender molecules. Under tensile loading, the aforementioned clay dispersion enhanced multiple cavitation processes, notably improving PLA shear flow.     

Polysaccharides from raw and cooked chayote modulate macrophage function

Chayote (Sechium edule) pulp is consumed raw or cooked and is source of polysaccharides with potential immunomodulatory properties in macrophages, which are cells that play important roles in homeostasis and innate immune responses to pathogens; however, these immunomodulatory effects of chayote polysaccharides remain unknown. Therefore, polysaccharides from raw (SeR) and cooked (SeC) chayote and from the hot water extract obtained after heating (SeH) were analyzed for their composition and effects on macrophages. Chayote has a high- (340 kDa) and a low- (46 kDa) molecular weight (MW) polysaccharide fraction containing high amounts of galactose, arabinose and galacturonic acid. After cooking, SeC was enriched in high-MW galactose-rich fractions, whereas SeH was enriched in low-MW arabinans and homogalaturonans-rich fractions. The polysaccharides induced tumor necrosis factor alpha (TNF-α) and nitric oxide (NO) secretion in macrophages; however, only SeR and SeH reduced TNF-α, NO and interleukin-6 secretion in activated macrophages. Furthermore, SeR and SeCW, but not SeC, affected phagocytic activity. In conclusion, bioactive polysaccharides in chayote modulate macrophage functions, and minor changes in composition resulting from the solubilization of a small proportion of low-MW arabinans and homogalacturonans during cooking accounted for the different effects of raw and cooked chayote.     

Logistics cost analysis of rice straw pellets for feasible production capacity and spatial scale in heat utilization systems: A case study in Nanporo town,Hokkaido, Japan

Rice straw is a promising renewable energy source because it is abundantly available in Asia. This study conducted a case study of logistics cost analysis for rice straw pellets by considering all stages in the supply chain to define the main factors affecting the selling price of rice straw pellets: collection (job-commission or employment of part-time workers), transportation, storage (vinyl greenhouses or storage buildings with larger capacity), pelletizing, and delivery to users with biomass boilers. The selling price was found to be strongly dependent on the production capacity because the investment cost for the pellet production facility had a significant effect of economies of scale. A production capacity of larger than 1500 t y⁻¹ is required for rice straw pellets to compete with wood pellets and fossil fuels in the studied Japanese context if the subsidy rate for the investment is 50%, part-time workers conduct the collection, and rice straw is stored in the storage buildings. Our sensitivity analysis also showed an economically feasible spatial scale: for example, rice straw should be collected within a 20 km radius and the users should be within a 38 km radius when the production capacity is 1500 t y⁻¹. In addition, other critical factors related to the collection of rice straw from the paddy fields and transportation of rice straw rolls to storage were identified as planning factors to further reduce the total logistics cost of rice straw pellets.     

Modeling moisture sorption isotherms in roasted green wheat using least square regression and neural-fuzzy techniques

Roasted green wheat at moisture content from 0.052 to 0.25 (decimal d.b.) and temperatures from 25 to 43 °C was used to model moisture sorption isotherms using conventional non-linear least square regression (NLR) and neural-fuzzy (NF) techniques. The results showed that neural-fuzzy techniques provided a better fit than conventional least square regression with: R² = 0.99 and 0.97, RMSE = 0.01 and 0.0038, E% = 1.01 and 5.9 and SSE = 0.0008 and 0.009, for NF and NLR techniques, respectively. Differential enthalpy decreased from 477.9 kJ/kg at 0.052 (decimal d.b. mc) to 44.7 kJ/kg at 0.25 (decimal d.b. mc) and entropy decreased from 1.16 kJ/kg K at 0.052 (decimal d.b. mc) to 0.014 kJ/kg K at 0.25 (decimal d.b. mc). A linear plot between enthalpy and entropy showed that compensation exists. The isokinetic temperature T_β was 376.13 K which was larger than the harmonic mean temperature T_hm = 307.31 K, showing that the water sorption was entropy-driven. The free energy change ΔG was positive (+38.42 kJ/kg) indicating a non-spontaneous water sorption process.     

Effects of high hydrostatic pressure treatment on structural,allergenicity, and functional properties of proteins from ginkgo seeds

The effects of high hydrostatic pressure (HHP) treatment on the structural, allergenicity and functional properties of ginkgo seed protein (GSP) were investigated. GSP was treated under pressures of 100, 200, 300, 400, 500, 600 and 700 MPa. Western blotting and ELISA assay revealed that HHP treatment at pressure ranges from 300 up to 700 MPa can significantly reduce the allergenicity of GSP. Meanwhile, SDS-PAGE, MALDI-TOF-MS, CD spectra, fluorescence spectra and UV absorption spectra analysis revealed that, after HHP treatment, the GSP disintegrated into proteins with small molecular weights ranging from 4 to 30 kDa; the secondary structures of α-helices and β-sheet were largely destroyed and turned into random coil; and the UV absorption intensity, surface hydrophobicity and sulfhydryl group (SH) content of GSP were significantly increased. Moreover, the HHP-treated GSP showed markedly improved heat stability and emulsifying properties compared to the untreated GSP.Industrial relevanceAs a traditional food and medicine source, the seeds of Ginkgo biloba were used in china for several thousand years. Ginkgo seeds could be added to desserts, glazed fruit, beverages and tipple, also ginkgo seeds, as a traditional Chinese medicinal material, have been recorded in the Compendium of Materia Medical. Research shows that ginkgo seeds have a relatively high content (10%–15%) of proteins, which possess rich and reasonable composition of amino acids, and much higher content of essential amino acids than the recommended FAO/WHO standard, belonging to the high-quality protein. Ginkgo seeds proteins (GSP) have many biological activities, including anti-oxidation, anti-aging, anti-tumor, and anti-bacterial, so it has high value of nutrition and medicine. However, eating GSP could result in allergic reaction to humans, infant, or children are more sensitive to GSP, the clinical symptoms such as nausea, vomiting, bellyache, diarrhea, dysphoria, exanimation, convulsions, dyspnea, and mydriasis, and sometimes even death can occur.In the study, we used the method of high hydrostatic pressure (HHP) treatments, which can significantly improve the functional properties and reduce the antigenicity of GSP. After the HHP treatment, GSP can be transformed into proteins with small molecular weights ranging from 4 to 30 kDa, the antigenicity of GSP can be reduced by more than 95%, and the heat stability and emulsifying properties of GSP can be markedly improved. Thus, this study is very helpful for designing the hypoallergenic and improved functional GSP, which could have a relevant practical application for their use as base ingredients of food.     

Enzymatic Writing to Soft Films: Potential to Filter,Store, and Analyze Biologically Relevant Chemical Information

Sensor‐based chemical analyses commonly enlist either the molecular recognition capabilities of biology (e.g., enzyme biosensors) or advanced information processing algorithms (e.g., the electronic nose). Here, a hybrid approach is proposed in which an enzyme is used to “filter” chemical information and write this information to a film which then serves as a permanent storage medium that can be ‘read’ repeatedly, interactively, and by multiple sensor modalities. This approach is demonstrated by analyzing common dietary phenols that are reported to offer health benefits. Specifically, the enzyme tyrosinase is used to convert these phenols into reactive quinones that graft (i.e., write) to a chitosan film. Grafting can be detected by optical, mechanical, and electrochemical sensors. Importantly, grafting confers redox activity to the films and this redox activity can be probed interactively by advanced electrochemical methods that allow the intrinsic redox reactivities to be compared, redox interactions to be identified, and biologically relevant redox activities to be examined. The transfer of chemical and biological information to a film is envisioned to provide broader access to the extensive capabilities offered by sensor technologies and signal processing methodologies.     

Controlled transglutaminase treatment in Edam cheese-making

Transglutaminase (TG) has been widely used in the dairy industry to increase product yield. However, it has not been used in the production of ripened cheeses because of the difficulty of controlling TG activity. It was observed that cross-linking of TG in ultrafiltration retentate could be controlled using a protein standardisation step. TG increased the cheese yield 4%, due to an increase in the moisture content of the cheeses. Traditionally, increased cheese moisture reduces hardness of cheese, but this was not observed in the cheese from TG-treated milk. Furthermore, the organoleptic properties of the TG-cheeses did not differ significantly from those of the control cheeses. No differences were observed in the protein profile of the whey fraction as a result of the TG treatment. The protein standardisation process thus makes it possible to use TG in the production of Edam cheese.     

Production of phage free cheese whey: Design of a tubular laboratory membrane filtration system and assessment of a feasibility study

An interposed “phage filtration” process step is proposed prior to subsequent processing of cheese whey to whey products to reduce fermentation risks due to phage contamination. At laboratory scale, the characteristics of three single tube ceramic membranes on the filtration performance in terms of phage retention, protein transmission and filtrate flux were analysed. From these tested membranes, a 0.1 μm microfiltration membrane was found to be suitable for significant phage reduction (3.4 log units) in cheese whey, simultaneously allowing total protein transmission of 56.2%. The experiments within the designed feasibility study conducted with a pilot plant microfiltration system provided a higher phage retention (4.1 log units) and a significantly increased transmission of major whey proteins (up to 84%) in comparison with the laboratory plant. The results shown in this study can easily be adapted by the dairy industry for better phage control and enhanced process safety.